Fire damper



J. C. KURZ FIRE DAMPER Dec. 1, 1976 2 Sheets-Sheet 1 Filed Feb. 19 9 2 -il W //W /0 Low d ww b i r w w owa m a Z MW H MKS M E w walk M JM an K v Y \L B J. C. KURZ Dec. 1, 1970 FIRE DAMPER 2 t e e h S t e e h S 2 Filed Feb. 6. 1969 ATTORNEY United States 3,543,440 FIRE DAMPER John C. Kurz, 8933 Krewstown Road, Philadelphia, Pa. 19115 Filed Feb. 6, 1969, Ser. No. 797,015 Int. Cl. E05f /20 US. Cl. 49-7 2 Claims ABSTRACT OF THE DISCLOSURE A multi-blade fire damper including spring clip means to secure the damper blade in closed position and means to easily depress the spring clip means to thereby disengage the blade when it is desired to again open the fire damper.

BACKGROUND OF THE INVENTION This invention relates in general to the field of building construction and more particularly, is directed to a novel type of fire damper locking device whereby fire damper blades may be positively locked in the closed position.

In the construction of modern buildings for office, in dustrial, commercial and other uses, it is common practice in the building industry to provide complex air handling systems within the building during the design and construction stages of the work. Such systems find utility in heating, ventilating, air conditioning and in certain other industrial and process applications. The air conditioning installations far exceed all others in number, size and dollar volume of construction and so the fire damper as referred to in the instant application will be discussed as it relates in particular to the air conditioning industry. However, it should be borne in mind that the application and the principles herein set forth are equally applicable to other air handling systems and in all other construc tions wherein it is desirable to install a fire damper.

Duct systems for air handling purposes have traditionally been constructed in buildings as one of the many usual design features and such systems in the past have formed a basis for considerable engineering research and technical improvements. Prior workers in the art have found that very often when designing air conditioning systems, air distribution design considerations have required that duct work pass through fire walls, fire divisions, fioors, shafts, separations between occupancies and other special areas such as mechanical equipment rooms. In such locations, most building codes and other safety standards require the installation of fire dampers to prevent the possible spread of heat and flame from one fire division area to another through the duct work itself. Accordingly, design engineers, mechanical contractors and other prior workers in the art have employed fire dampers to provide safety from fire considerations at the critical locations so designated for additional protection by the safety standards.

In view of the complexity of many buildings, it can well be appreciated that numerous fire dampers must be fabricated and installed in order to provide the building occupants with the greatest possible safety from fire. Accordingly then, it can be demonstrated that the cost of fabrication and installation of fire dampers represents a significant percentage of the total initial cost of the building construction. In view of the importance of such fire safety devices, the construction and operation of fire dampers are closely regulated and controlled by fire safety officials; insurance companies, fire departments and others. As part of the control exercised in this area of construction, in most jurisdictions, fire dampers must be approved prior to installation by recognized testing laboratories such as Underwriters Laboratories, Inc. Such approvals are close- 3,543,44fi Patented Dec. 1, 1970 1y regulated in accordance with standard fire safety tests which have been established to test the performance of fire dampers under the severest type of conditions, including all of the stresses that may be anticipated as a result of severe fire conditions. Prior workers in the field have found that fire dampers must be carefully fabricated, properly designed and of quality construction in order to perform satisfactorily under the severe test conditions imposed. Because of this, the usual production line techniques which might otherwise be employed to effect savings in cost to thereby lower the final cost to the building owner have proved unsatisfactory. Generally speaking, every attempt to save production costs has resulted in a fire damper of substandard construction that could not satisfactorily perform under the aforementioned fire test conditions.

SUMMARY OF THE INVENTION The present invention includes a novel method of locking fire dampers in the closed position by utilizing spring locks affixed to the fire damper frame construction which cooperate with locking plates affixed to the bottom fire damper blade. The spring locks are provided with manually operated spring clip depressing devices which facilitate releasing the locks from the spring clips when resetting fire damper blades in areas having restricted working room.

A study of prior art fire dampers indicates that in most instances, failure to perform satisfactorily was a direct result of the failure of the hardware or of the latching construction to hold the fire damper blades in closed position during the entire test duration. The present invention seeks to provide low cost, positive, spring bias latching that will positively close the fire damper blades under all conditions. Further, in view of the positive locking features provided by the present invention, savings may now be realized in constructing other portions of the fire damper wherein production savings can now be effected.

Accordingly, it is an object of the present invention to provide an improved fire damper of the type set forth.

It is another object of the present invention to provide a novel fire damper that includes spring biased blade latching means.

It is another object of the present invention to provide a novel fire damper including spring biased blade latching means and further including means for manually adjusting the latching means.

It is a further object of the present invention to provide a novel fire damper having spring biased latching means that are readily releasable by workmen using ordinary hand tools.

It is another object of the present invention to provide a novel fire damper including spring biased latching means that may be readily released or adjusted by a workman even when located in restricted or inaccessible areas.

It is another object of the present invention to provide a novel fire damper that is inexpensive in manufacture, rugged in construction and trouble-free when in use.

Other objects and a fuller understanding of the invention will be had by referring to the following description and claims of preferred embodiment thereof, taken in conjunction with the accompanying drawings wherein like reference characters refer to similar parts throughout the several views and in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the invention in closed and locked position.

FIG. 2 is a cross-sectional view taken along line 22 of FIG. 1, looking in the direction of the arrows and showing the fire damper blades in open position.

e FIG. 3 is a view similar to FIG. 2 and showing the fire damper blades in closed and latched position.

FIG. 4 is a detail perspective view of the spring lock in locked position.

FIG. 5 is a detail perspective view similar to FIG. 4 showing the spring lock as it receives the locking plate.

FIG. 6 is a detail perspective view similar to FIG. 4 showing the spring lock depressed by the adjusting bolt.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTIONS Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of my invention selected for illustration in the drawings and are not intended to define or limit the scope of the invention.

Referring now to the drawings, I show in FIG. 1 a parallel blade, pivoting type of fire damper generally designated 10 which is suitable for installation in a building duct section (not shown) in the usual manner. The damper includes a peripheral damper frame 12 of generally rectangular configuration formed of galvanized steel of sufficient gage to adequately support the damper blades in well-known manner. A plurality of galvanized steel roll formed blades 14, 50 pivotally function within the frame 12 and turn about the right and left pivot pins 16 which rotate in bronze oilite bearings 32 in the usual manner from an open position 42 as shown in FIG. 2 to a closed, interlocking position 52 as best seen in FIG. 3.

Each blade 14, 50 carries a linkage bracket 18 which rigidly affixes to the lower half thereof by riveting or spot welding to simultaneously operate the plurality of blades 14, 50 in cooperation with the vertical tie bar 20. Each linkage bracket 18 connects respectively to the tie bar 20 by utilizing loosely fitting rivets 22 in such manner that the tie bar 20 serves to open and close the damper blades 14, 50 by vertical reciprocal movement. The individual blades 14, 50 are urged to simultaneously pivot about the laterally positioned pivot pins 16 from the open position 42 to the closed position 52 upon action of the tie bar 20 which is operatively pinned to the respective brackets 18.

As best seen in FIG. 2, the blades 14 are held in the open position 42 by means of the cinching assembly 26 which comprises two lengths of copper wire 44 and a conventional fusible link 24 interconnected therewith. A cinching bracket angle 28 medially afiixes to the top of the frame 12 and secures one end of the wire 44 in stationary relationship. The other end of the wire 44 connects to the tie bar 20 and secures the tie bar in its upward position thereby rotating the damper blades, 14, 50 to their open position 42 by utilizing the respective brackets 18 and rivets 22. The closure springs bias between the frame afiixed angle clips 46 and an angle clip 48 which is afiixed to the lower most damper blade 5t] to thereby tension the wire 44.

It will be noted that upon melting of the fusible link 24, the bias of the springs 30 pulls the damper blades 14, 50 about the respective pivot pins 16 to thereby urge all of the blades 14, 50 to their respective closed positions 52 through the cooperating action of the linkage bracket 18 and the tie bar 20. Referring now to FIG. 3 it will be observed that once the fusible link 24 melts upon the application of sufiicient heat, usually one hundred and sixty-five degrees (165 F.), the wire 44 severs and the springs 30 pivot the respective blades 14, 5a to the closed position 52 through the interaction of the angle clip 48, the afiixed damper blade 50, the interconnected linkage brackets 18, the connecting tie bar 20 and the damper blades 14. The lowest damper blade 50 abuts the frame afiixed angle stop 38 in the closed position 52 to thereby secure the blades 14, 50 in their closed position.

Referring now to FIGS. 1 and 4, the action of the spring steel locks 54, 54 is illustrated. Each lock 54, 54' comprises a generally L-shaped spring steel engaging arm 56 which is afiixed at one end 58 thereof to the peripheral frame 12 in well-known manner such as by riveting or spot welding. The free side 60, 60' of each arm 56 is provided with an oversized hole 68 near the free end thereof and positions generally parallel with the frame 12. The spring construction of the spring arm 56 opposes any movement out of the parallel relationship with the said frame 12. A cooperating notched locking plate 62, 62 afiixes near the bottom of the lowest damper blade in alignment with the free edge 64 of the spring arm free side 60, A bottom, medially positioned notch 74 is provided in the locking plate 62, 62 to provide clearance over the bolt 66 as hereinafter more fully explained. The slotted head, lock adjusting bolt 66 inserts through the hole 68 in loose relationship therewith and threadedly turns into a threaded opening 70 which is drilled and tapped into the adjacent frame portion 12. The head 72 of the bolt 66 is larger in diameter than the hole 68 and thereby engages and serves to depress the free side 60 of the spring arm 56 when the bolt 66 is turned into the threaded opening 70.

As can be readily observed in FIG. 2, the spring bias of the free side 60 of the spring lock 54 serves to position the side 60 in parallel, spaced relationship from the frame 12 when the bolt 66 is upwardly turned in the threaded opening 70 and the bolt head 72 raises out of engagement with the free side 60. In this position, upon melting of the fusible link 24, the blades 14, 50 pivot downwardly to the closed position 52 under urging of the springs 30 as hereinabove set forth. The bottom of the locking plates 62, 62 contact the free sides 60, 60' as the damper blades swing closed, thereby depressing the arms 60, 60 against the natural spring bias of the spring locks 54, 54'. See FIG. 5. It will be observed that the notch 74 swings clear of the bolt 66 thereby permitting the locking plates 62, 62' to slide completely past the free edges 64 of the free sides 60, 60 under urging of the springs 30. As best observed in FIGS. 3 and 4, once the locking plate 62 clears the free edge 64 of the free sides 60, 60' the natural resiliency of the free sides causes them to respectively return to the initial, generally parallel position, thereby engaging the bottom of the locking plates 62, 62' against the free edges 64 of the locks 54, 54'. In this manner, the cooperating locking plates 62, 62' and the free sides 60, 60' serve to positively lock the fire damper blade 50 and the tie bar connected blades 14 in their closed position 52.

In order to release the fire damper blades 14, 50 and allow them to swing back to the open position 42 as in FIG. 2, each free arm 60, 60 must be depressed a suflicient distance against the spring bias of the spring locks 54, 54' to permit the bottom of the locking plates 62 to swing clear over the top of the free sides 60, 60'. In those installations where the fire damper 10 is installed in an accessible position, a workman need simply depress the free sides 60, 60' of the spring locks 54, 54' by utilizing both hands until the blades 14, 50 swing free upon urging the free sides 60, 60 out of engagement with the locking plates 62, 62'. A new fusible link 24 can be then installed in the wire 44 and the entire device will thus be activated by pulling the tie bar 20 upwardly to assume the position of FIG. 2.

The present invention finds special utility in inaccesible locations wherein a workman may be able to utilize only one arm at a time to reset the fire damper 10 after it has pivoted to the closed position 52. In such instances, the workmen need simply turn the bolts 66 downwardly by employing a screw-driver in engagement with the slotted heads 72 in the usual manner. In this manner, each threaded bolt 66 may be individually downwardly turned into the threaded opening 70 provided in the frame 12 to thereby engage the bottom of the bolt head 72 respectively upon each free side 60. By continued turning of the bolt 66, the free sides 60 can be downwardly urged, one at a time, until such time as each free edges 64 swings clear below the bottom of the locking plates 62, 62'. Ac-

cordingly, a single workman, by utilizing only one arm in a tight location, can individually depress the free sides 60, 60' and thereby release the blades 14, 50 to permit them to be pivoted back to the open position 42 against the bias of the springs 30. After each locking plate 62, 62' has cleared the respective free edges 64 of the free side 60, 60', the bolts 66 may then be loosened in the usual manner to permit the free sides 60, 60" to assume their natural parallel position as in FIG. 2 to thereby again permit locking engagement of the locking plates 62, 62' upon the free edges 64 of the spring locks 54, 54' should the reset fire damper again function.

What is claimed is:

1. In a fire damper assembly of the type including a supporting frame and having a plurality of operating blades pivotally arranged within the frame wherein operating linkage pivots the blades from an open position to a closed position in unison, the improvement comprising:

(A) a spring lock afiixed to the said frame and positioned to retain the bottom-most said operating blade,

(1) the said spring lock including a spring arm having a frame affixed end and a free end,

(a) the said free end having an initial position and a depressed position,

(.1) the said free end positioning in generally spaced, parallel relationship to l the said frame when in the said initial position;

(B) a locking plate cooperating with the said spring lock,

1 (l) the said lockting plate being aflixed to the bottom-most said operating blade in alignment with the said spring lock,

(a) said locking plate extending below the bottom of the bottom-most blade,

(2) the said locking plate engaging upon the free end of the spring arm when the blades are rotated to the closed position to thereby lock 1 the said blades,

(3) the said locking plate momentarily depressing the said spring arm to its depressed position as the blades pivot from the open position to the closed position,

(4) the spring bias of the said spring arm returning the free end to its said initial position when the blades reach their closed position to thereby engage the edge of the spring arm against the said locking plate;

(C) spring lock depressing means functioning to depress the said spring arm out of engagement with the said locking plate when the blades are rotated to the said closed position,

(1) said means including a threaded adjusting bolt threadedly engaging into the said frame,

(2) said spring arm being provided with an opening to loosely receive the said bolt therethrough,

(a) the said bolt being equipped with a head of larger diameter than the said opening,

(.1) the said head engaging the spring arm when the bolt threadedly engages into the frame to thereby depress the spring arm below its initial position, (b) the said bolt depressing the spring arm for an extended length of time; and

(D) notch means provided in the said locking plate,

(1) said not-ch means providing sufiicient clearance over the said bolt to permit the locking plate to swing past the bolt when the spring arm situates in its initial position.

2. The invention of claim 1 wherein the said adjusting bolt is provided with a slotted head.

References Cited UNITED STATES PATENTS 553,499 1/ 1896 Fisher 29287 757,298 4/ 1904 Haliday 292-87 1,871,161 8/1932 Dickson 49--7 2,042,297 5/ 1936 Craighead 292-87 2,210,869 8/ 1940 Larson 4974 X 3,353,857 11/1967 Mongor 49394 X 3,260,018 7/1966 Schuh 497 DENNIS L. TAYLOR, Primary Examiner 

